These tiny cell components are a big topic of discussion in the scientific community nowadays, especially among researchers interested in how we age. It turns out that the length of your telomeres says a lot about your overall health and how quickly you're aging. Intrigued? Here's what you need to know about them.

What is a telomere?

Tiny caps on each end of the 46 chromosomes found in a human cell—similar to the plastic tips at the ends of shoelaces—telomeres protect cells from damage when they divide. Without them, genetic material would be lost during cell division. But telomeres pay the price for protecting DNA. “Every time a cell divides, telomeres get a little shorter,” explains Dr. Jerry W. Shay, professor in the department of cell biology at UT Southwestern Medical Center in Dallas.

Telomeres serve as biological records of how many times cells have divided: The shorter the telomere, the more times cell division has occurred. When telomeres get too short, cell division stops, causing senescence, or cell aging. It is perfectly normal for telomeres to shorten over time. But telomeres that are too short for your chronological age may accelerate the aging process. Shorter telomeres have also been associated with an increased risk of cancer, cardiovascular disease, cognitive decline and dementia. One study found that heart attack risk among younger patients (age 73 or younger) with shorter telomeres was three times as high as the risk among older patients.

What makes telomeres short?

Baseline telomere length is determined partly by genetics, and there is a natural decline with age. But your lifestyle can have a major influence on the rate at which your telomeres shorten. “Perhaps two-thirds of it is what you do to your body during your lifetime,” says Shay. “If your telomeres are too short for your chronological age, that means you are doing something wrong.” So-called environmental stressors—eating unhealthy food, smoking, drinking too much, or not exercising enough—increase cell damage and may chip away at telomeres. The air quality where you live can also play a role: Your telomeres will shorten faster if you live in, say, Beijing, than if you dwell in a place like Montana, where the air is clean, notes Shay.

Stress and anxiety can shorten telomeres, too. A 2012 study in the journal PloS One found that middle-aged and older women who were prone to acute anxiety due to phobias—fear of things like crowds or heights—had shorter telomeres than women who weren't anxious. In fact, the telomeres of phobic women were equivalent to the lengths of telomeres in women six years older. Another study published in 2004 found that women who cared for a chronically ill child had shorter telomeres on average than women whose children were healthy. In fact, based on telomere length, the mothers of the sick children had telomere lengths equivalent to those of people at least a decade older.

Page 2 of 3 - Can you improve telomere length?

If your telomeres aren’t as long as they should be, it doesn’t mean you're doomed. Fortunately, cells produce telomerase, an enzyme that minimizes DNA damage and replaces some of that lost telomere. Plus, research has found that the same healthy behaviors that are good for your heart can increase levels of telomerase and rebuild some of your telomeres. For instance, a study published in the journal Psychoneuroendocrinology reported that people who meditated for about six hours a day for three months boosted their telomerase levels significantly compared to non-meditators. In another study, Ohio State University researchers found that overweight, sedentary adults who took supplements containing either 2.5g or 1.25g of active omega-3 polyunsaturated fatty acids daily for four months actually lengthened their telomeres.

There are no firm guidelines for how much meditation you should do to lengthen telomeres; Shay suggests lowering stress levels in general, using whatever method works for you. And while moderate exercise can also stall telomere decline (or increase length), stick to walking or other low-impact exercise, Shay advises. "Running causes wear and tear on the joints," says Shay, and that can shorten telomeres.

How to determine your telomere length

Telomere length is measured by using a molecular test, which counts the number of nucleotides—or molecules—in each telomere. “A healthy 50-year-old might have 8,000 or 9,000 nucleotides,” says Shay. “A not-so-healthy 50 something might have 4,000.”

But keep in mind: It's the shortest telomeres on each chromosome end that count, not the average length of telomeres, says Shay. “It only takes a few critically shortened telomeres to initiate cell aging,” he adds.

Currently, a blood test, Telomere Analysis Technology (TAT), is available to measure short telomeres—those responsible for cell senescence and the onset of age-related diseases. It's offered by a company called Life Length, based in Madrid, Spain. Cost of the test, which isn’t covered by insurance, averages $800, though it's expected to drop. Life Length has a network of 500 doctors in the U.S. who can take your blood and send it to the company's lab for analysis. (Full disclosure: Shay is a member of the Scientific Advisory Board of Life Length, creator of TAT.) Saliva tests are also being developed by another company.

Shay believes that one day measuring people's telomeres will be as routine as measuring their cholesterol levels. For now, though, telomere testing is expensive, and there’s that making the lifestyle changes to address shortening telomeres—like lowering stress or stopping smoking—will add years to your life or lower your risk for age-related diseases. Researchers are continuing to study the role of telomeres in aging and how best to use the information telomere testing yields. Knowing how your telomeres are faring may give you the motivation you need to overhaul your habits, possibly slowing down the aging process. That alone should put a spring in your step.